Re: [PATCH v3 2/2] rtc: ds1307: Add support for Epson RX8111

Alexandre Belloni
2022-11-14T22:35:13Z

I should have commented on this patch but my comment is still valid,
even more so that the alarm handling is bloating the driver.

On 07/11/2022 09:54:08+0100, Mike Looijmans wrote:
> The rx_8111 is quite similar to the rx_8030. This adds support for this
> chip to the ds1307 driver. Date/time and alarm registers are in the
> usual places. The nvmem is located at 0x40. Time stamping is not
> supported.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
>
> ---
>
> Changes in v3:
> Wrong version of code sent in v2
> Attempt to fix e-mail sending issues
>
> Changes in v2:
> Add "_REG" in register names
> Add interrupt/alarm handling (different from rx8030)
>
> drivers/rtc/rtc-ds1307.c | 306 ++++++++++++++++++++++++++++++++++++---
> 1 file changed, 284 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index d51565bcc189..5aeb5732bae5 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -46,6 +46,7 @@ enum ds_type {
> m41t11,
> mcp794xx,
> rx_8025,
> + rx_8111,
> rx_8130,
> last_ds_type /* always last */
> /* rs5c372 too? different address... */
> @@ -113,6 +114,24 @@ enum ds_type {
> # define RX8025_BIT_VDET 0x40
> # define RX8025_BIT_XST 0x20
>
> +#define RX8111_REG_EXTENSION 0x1d
> +# define RX8111_REG_EXTENSION_WADA BIT(3)
> +#define RX8111_REG_FLAG 0x1e
> +# define RX8111_REG_FLAG_VLF BIT(1)
> +# define RX8111_REG_FLAG_EVF BIT(2)
> +# define RX8111_REG_FLAG_AF BIT(3)
> +# define RX8111_REG_FLAG_TF BIT(4)
> +# define RX8111_REG_FLAG_UF BIT(5)
> +#define RX8111_REG_CONTROL 0x1e
> +# define RX8111_REG_CONTROL_EIE BIT(2)
> +# define RX8111_REG_CONTROL_AIE BIT(3)
> +# define RX8111_REG_CONTROL_TIE BIT(4)
> +# define RX8111_REG_CONTROL_UIE BIT(5)
> +#define RX8111_REG_PWR_SWITCH_CTRL 0x32
> +# define RX8111_PSC_SMP_INIEN BIT(6)
> +# define RX8111_PSC_SMP_CHGEN BIT(7)
> +#define RX8111_REG_TIME_STAMP_BUF_CTRL 0x34
> +
> #define RX8130_REG_ALARM_MIN 0x17
> #define RX8130_REG_ALARM_HOUR 0x18
> #define RX8130_REG_ALARM_WEEK_OR_DAY 0x19
> @@ -205,6 +224,68 @@ struct chip_desc {
>
> static const struct chip_desc chips[last_ds_type];
>
> +static int ds1307_check_voltage_lost(struct ds1307 *ds1307)
> +{
> + int ret;
> + unsigned int reg;
> + unsigned int mask;
> + unsigned int regflag;
> +
> + switch (ds1307->type) {
> + case rx_8111:
> + reg = RX8111_REG_FLAG;
> + mask = RX8111_REG_FLAG_VLF;
> + break;
> + case rx_8130:
> + reg = RX8130_REG_FLAG;
> + mask = RX8130_REG_FLAG_VLF;
> + break;
> + default:
> + return 0;
> + }
> +
> + ret = regmap_read(ds1307->regmap, reg, &regflag);
> + if (ret) {
> + dev_err(ds1307->dev, "%s error %d\n", "read", ret);
> + return ret;
> + }
> +
> + if (regflag & mask) {
> + dev_warn_once(ds1307->dev, "oscillator failed, set time!\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int ds1307_clear_voltage_lost(struct ds1307 *ds1307)
> +{
> + int ret;
> + unsigned int reg;
> + unsigned int mask;
> +
> + switch (ds1307->type) {
> + case rx_8111:
> + reg = RX8111_REG_FLAG;
> + mask = (unsigned int)~RX8111_REG_FLAG_VLF;
> + break;
> + case rx_8130:
> + reg = RX8130_REG_FLAG;
> + mask = (unsigned int)~RX8130_REG_FLAG_VLF;
> + break;
> + default:
> + return 0;
> + }
> +
> + ret = regmap_write(ds1307->regmap, reg, mask);
> + if (ret) {
> + dev_err(ds1307->dev, "%s error %d\n", "write", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int ds1307_get_time(struct device *dev, struct rtc_time *t)
> {
> struct ds1307 *ds1307 = dev_get_drvdata(dev);
> @@ -212,19 +293,9 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
> const struct chip_desc *chip = &chips[ds1307->type];
> u8 regs[7];
>
> - if (ds1307->type == rx_8130) {
> - unsigned int regflag;
> - ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, &regflag);
> - if (ret) {
> - dev_err(dev, "%s error %d\n", "read", ret);
> - return ret;
> - }
> -
> - if (regflag & RX8130_REG_FLAG_VLF) {
> - dev_warn_once(dev, "oscillator failed, set time!\n");
> - return -EINVAL;
> - }
> - }
> + ret = ds1307_check_voltage_lost(ds1307);
> + if (ret)
> + return ret;
>
> /* read the RTC date and time registers all at once */
> ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
> @@ -397,15 +468,9 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
> return result;
> }
>
> - if (ds1307->type == rx_8130) {
> - /* clear Voltage Loss Flag as data is available now */
> - result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
> - ~(u8)RX8130_REG_FLAG_VLF);
> - if (result) {
> - dev_err(dev, "%s error %d\n", "write", result);
> - return result;
> - }
> - }
> + result = ds1307_clear_voltage_lost(ds1307);
> + if (result)
> + return result;
>
> return 0;
> }
> @@ -541,6 +606,174 @@ static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
> return setup;
> }
>
> +static u8 do_trickle_setup_rx8111(struct ds1307 *ds1307, u32 ohms, bool diode)
> +{
> + /* make sure that the backup battery is enabled */
> + u8 setup = RX8111_PSC_SMP_INIEN;
> +
> + if (diode)
> + setup |= RX8111_PSC_SMP_CHGEN;
> +
> + return setup;
> +}
> +
> +static irqreturn_t rx8111_irq(int irq, void *dev_id)
> +{
> + struct ds1307 *ds1307 = dev_id;
> + irqreturn_t result = IRQ_NONE;
> + int ret;
> + u8 ctl[2];
> + u8 flags = 0;
> +
> + rtc_lock(ds1307->rtc);
> +
> + /* Read flag and control registers. */
> + ret = regmap_bulk_read(ds1307->regmap, RX8111_REG_FLAG, ctl,
> + sizeof(ctl));
> + if (ret < 0)
> + goto out;
> +
> + if (ctl[0] & RX8111_REG_FLAG_AF) {
> + result = IRQ_HANDLED;
> + flags |= RTC_AF; /* Alarm */
> + ctl[1] &= ~RX8111_REG_CONTROL_AIE;
> + }
> + /*
> + * If an interrupt occurred that we cannot process, we'll have to turn
> + * it off, otherwise we'd be called again and again.
> + */
> + if (ctl[0] & RX8111_REG_FLAG_UF) {
> + result = IRQ_HANDLED;
> + ctl[1] &= ~RX8111_REG_CONTROL_UIE;
> + }
> + if (ctl[0] & RX8111_REG_FLAG_TF) {
> + result = IRQ_HANDLED;
> + ctl[1] &= ~RX8111_REG_CONTROL_TIE;
> + }
> + if (ctl[0] & RX8111_REG_FLAG_EVF) {
> + result = IRQ_HANDLED;
> + ctl[1] &= ~RX8111_REG_CONTROL_EIE;
> + }
> + /* Clear all flags */
> + ctl[0] &= ~(RX8111_REG_FLAG_UF | RX8111_REG_FLAG_TF |
> + RX8111_REG_FLAG_AF | RX8111_REG_FLAG_EVF);
> +
> + ret = regmap_bulk_write(ds1307->regmap, RX8111_REG_FLAG, ctl,
> + sizeof(ctl));
> + if (ret < 0)
> + goto out;
> +
> + rtc_update_irq(ds1307->rtc, 1, flags | RTC_IRQF);
> +
> +out:
> + rtc_unlock(ds1307->rtc);
> +
> + return result;
> +}
> +
> +static int rx8111_read_alarm(struct device *dev, struct rtc_wkalrm *t)
> +{
> + struct ds1307 *ds1307 = dev_get_drvdata(dev);
> + u8 ald[3], ctl[2];
> + int ret;
> +
> + /* Read alarm registers. */
> + ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
> + sizeof(ald));
> + if (ret < 0)
> + return ret;
> +
> + /* Read flag and control registers. */
> + ret = regmap_bulk_read(ds1307->regmap, RX8111_REG_FLAG, ctl,
> + sizeof(ctl));
> + if (ret < 0)
> + return ret;
> +
> + t->enabled = !!(ctl[1] & RX8111_REG_CONTROL_AIE);
> + t->pending = !!(ctl[0] & RX8111_REG_FLAG_AF);
> +
> + /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
> + t->time.tm_sec = -1;
> + t->time.tm_min = bcd2bin(ald[0] & 0x7f);
> + t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
> + t->time.tm_wday = -1;
> + t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
> + t->time.tm_mon = -1;
> + t->time.tm_year = -1;
> + t->time.tm_yday = -1;
> + t->time.tm_isdst = -1;
> +
> + dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
> + __func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
> + t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);

%ptR ?

> +
> + return 0;
> +}
> +
> +static int rx8111_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> +{
> + struct ds1307 *ds1307 = dev_get_drvdata(dev);
> + u8 ald[3], ctl[3];
> + int ret;
> +
> + dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
> + "enabled=%d pending=%d\n", __func__,
> + t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
> + t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
> + t->enabled, t->pending);
> +
%ptR ?

Is that even useful as there is already a tracepoint that is always
available?

> + /* Read control registers. */
> + ret = regmap_bulk_read(ds1307->regmap, RX8111_REG_EXTENSION, ctl,
> + sizeof(ctl));
> + if (ret < 0)
> + return ret;
> +
> + ctl[0] &= RX8111_REG_EXTENSION_WADA;
> + ctl[1] &= ~RX8111_REG_FLAG_AF;
> + ctl[2] &= ~RX8111_REG_CONTROL_AIE;
> +
> + ret = regmap_bulk_write(ds1307->regmap, RX8111_REG_EXTENSION, ctl,
> + sizeof(ctl));
> + if (ret < 0)
> + return ret;
> +
> + /* Hardware alarm precision is 1 minute! */

Instead of a comment here, you should set rtc->features properly

> + ald[0] = bin2bcd(t->time.tm_min);
> + ald[1] = bin2bcd(t->time.tm_hour);
> + ald[2] = bin2bcd(t->time.tm_mday);
> +
> + ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
> + sizeof(ald));
> + if (ret < 0)
> + return ret;
> +
> + if (!t->enabled)
> + return 0;
> +
> + ctl[2] |= RX8111_REG_CONTROL_AIE;
> +
> + return regmap_write(ds1307->regmap, RX8111_REG_CONTROL, ctl[2]);
> +}
> +
> +static int rx8111_alarm_irq_enable(struct device *dev, unsigned int enabled)
> +{
> + struct ds1307 *ds1307 = dev_get_drvdata(dev);
> + int ret, reg;
> +
> + ret = regmap_read(ds1307->regmap, RX8111_REG_CONTROL, &reg);
> + if (ret < 0)
> + return ret;
> +
> + if (enabled)
> + reg |= RX8111_REG_CONTROL_AIE;
> + else
> + reg &= ~RX8111_REG_CONTROL_AIE;
> +
> + dev_dbg(dev, "%s, enable=%u, reg=0x%x\n", __func__, enabled, reg);
> +
> + return regmap_write(ds1307->regmap, RX8111_REG_CONTROL, reg);
> +}
> +
> static u8 do_trickle_setup_rx8130(struct ds1307 *ds1307, u32 ohms, bool diode)
> {
> /* make sure that the backup battery is enabled */
> @@ -943,6 +1176,14 @@ static const struct rtc_class_ops rx8130_rtc_ops = {
> .alarm_irq_enable = rx8130_alarm_irq_enable,
> };
>
> +static const struct rtc_class_ops rx8111_rtc_ops = {
> + .read_time = ds1307_get_time,
> + .set_time = ds1307_set_time,
> + .read_alarm = rx8111_read_alarm,
> + .set_alarm = rx8111_set_alarm,
> + .alarm_irq_enable = rx8111_alarm_irq_enable,
> +};
> +
> static const struct rtc_class_ops mcp794xx_rtc_ops = {
> .read_time = ds1307_get_time,
> .set_time = ds1307_set_time,
> @@ -1012,6 +1253,16 @@ static const struct chip_desc chips[last_ds_type] = {
> .century_bit = DS1337_BIT_CENTURY,
> .bbsqi_bit = DS3231_BIT_BBSQW,
> },
> + [rx_8111] = {
> + .alarm = 1,
> + .nvram_offset = 0x40,
> + .nvram_size = 0x40, /* 0x40 .. 0x7F is user RAM */
> + .offset = 0x10,
> + .irq_handler = rx8111_irq,
> + .rtc_ops = &rx8111_rtc_ops,
> + .trickle_charger_reg = RX8111_REG_PWR_SWITCH_CTRL,
> + .do_trickle_setup = &do_trickle_setup_rx8111,
> + },
> [rx_8130] = {
> .alarm = 1,
> /* this is battery backed SRAM */
> @@ -1063,6 +1314,7 @@ static const struct i2c_device_id ds1307_id[] = {
> { "pt7c4338", ds_1307 },
> { "rx8025", rx_8025 },
> { "isl12057", ds_1337 },
> + { "rx8111", rx_8111 },
> { "rx8130", rx_8130 },
> { }
> };
> @@ -1137,6 +1389,10 @@ static const struct of_device_id ds1307_of_match[] = {
> .compatible = "isil,isl12057",
> .data = (void *)ds_1337
> },
> + {
> + .compatible = "epson,rx8111",
> + .data = (void *)rx_8111
> + },
> {
> .compatible = "epson,rx8130",
> .data = (void *)rx_8130
> @@ -1880,6 +2136,12 @@ static int ds1307_probe(struct i2c_client *client,
> DS1307_REG_HOUR << 4 | 0x08, hour);
> }
> break;
> + case rx_8111:
> + /* Use memory as user RAM */
> + regmap_write(ds1307->regmap, RX8111_REG_TIME_STAMP_BUF_CTRL, 0);
> + /* Disable timer, events, frequency output */
> + regmap_write(ds1307->regmap, RX8111_REG_EXTENSION, 0xc8);
> + break;
> case ds_1388:
> err = regmap_read(ds1307->regmap, DS1388_REG_CONTROL, &tmp);
> if (err) {
> --
> 2.17.1
>

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering